Do Not Disturb is a feature that allows you to silence calls, alerts, and notifications that you get while your device is locked. That way you won’t be distracted by those annoying notifications. Here’s how to set it up.
Go to your phone “Settings”.
Scroll Down and click on the “Do Not Disturb” option.
At the very top of the list, tap “Do Not Disturb” to turn it on. The toggle should turn green once you’ve enabled it. (there’ll be a moon icon in the status bar)
While you’re there, tap “Allow Calls From”.
You’ll see a list of options, at the bottom select “All Contacts”. You should see a small check mark appear on the right side.
This would enable your iPhone to only ring when receive calls from people on address book and silence all unknown and no caller ID callers.
2. Block No Caller ID Using Contacts
Another simple way to block those No Caller ID calls is by creating a new contact. Yes, you’ll create a new contact on your iPhone and name it “No Caller ID”, “No Number” or “Do Not Answer”.
Go to “Contacts”, tap the “+” sign at the top right corner. Enter 000-000-0000 for the phone number. Next, open the phone app, find the new contact you just created and select it. Scroll down and tap “Block this caller”.
A popup window will appear letting you know what happens when you block a contact. Tap Block Contact to confirm our decision.
Another way to do that is to go to your iPhone Settings. Tap “Phone”, scroll down and tap “Blocked Contacts”. You may see a list of blocked callers if you’ve already blocked people on your contact list before. Tap “Add New…”, it will take you to your Contacts list so you can pick the annoying caller.
3. Using cell phone carriers
While iOS gives you couple options to block unwanted calls, the best way to block No Caller ID is through your wireless service provider.
Most cell phone carriers offer some sort of call filter services. Here’re what the most popular networks in the U.S. offer.
AT&T Mobile Security and Call Protect offers two plans. A basic version, which is free but offers limited features. The Plus version costs $3.99/month and offers more protection. Visit Block Robocalls and Unwanted Calls for more info.
T-Mobile mobile security service has three plans. “Scam ID” and “Scam block”, which are included in your cell phone plan. They identify and filter out calls from scammers. T-Mobile also offers a premium plan: “Name ID”. It costs $4/month and helps identify, screen, reverse search, and block calls. Learn more at Blocking Scams and Unwanted Calls
Verizon’s Call Filter service offers two tiers pricing. With the free plan you get spam detection, blocking and reporting. The Call Filter Plus, which costs $2.99/mo or $7.99/mo for a single line or accounts with 3 or more eligible lines, respectively. Visit Stop Unwanted Calls for more info.
Sprint offers two plans: a free basic plan and a premium plan which offers more features but will cost you $2.99/month. Find more info at Stop Unwanted Calls.
National Do Not Call Registry
You could also register your home or mobile phones with the National Do Not Call Registry. To register: